An introduction of an object into an electromagnetic field can change the tuning of an antenna's field. The antenna's field can be detuned or degraded by having a frequency of the antenna's drift away from the resonant frequency of the antenna. For example, within a certain distance threshold, a NFC enabled object can degrade the tuning of a NFC antenna as the object gets closer to the antenna. The most extreme such cases is the zero centimeter case—wherein the NFC enabled object is zero centimeters or adjacent to the NFC antenna, and the NFC antenna detunes the most.
The detuning of an antenna can have adverse effects to the antenna's function. For example, in the zero centimeter case described above, the NFC antenna requires greater power to read the NFC enabled object.
Detuning of an antenna is exacerbated by smaller antennas, as are commonly found in mobile payment devices.